Preparation method and application of cinnamoyl derivative-based disulfide compound

Abstract

The invention relates to a preparation method and application of a cinnamyl derivative-based disulfide compound, belongs to the field of high polymer chemical materials and photopolymerization, and is provided based on obvious volume shrinkage of LED free radical photopolymerization. The cinnamyl derivative-based disulfide compound has the beneficial effects that the disclosed cinnamyl derivative-based disulfide compound can reduce volume shrinkage of free radical photopolymerization induced by 455nm LED light, and also has the characteristics of initiation, polymerization and photobleaching. Moreover, the disulfide can improve the thermal stability, friction resistance and hardness of the photocuring material, and has a great application prospect in the field of long-wavelength LED photopolymerization.

Description

Technical Field

[0001] This invention relates to LED photopolymerization systems, and describes a method for preparing and using a cinnamic yl derivative disulfide compound with photoinitiation and volume shrinkage reduction capabilities, belonging to the field of polymer chemical materials technology. Background Technology

[0002] In traditional ultraviolet (UV) photopolymerization, mercury lamps are primarily used as the light source to initiate the photopolymerization system. However, due to the high energy consumption, low safety factor, and tendency to produce harmful gases such as ozone from mercury lamps, UV photopolymerization using traditional mercury lamps is gradually being replaced by LED photopolymerization. Free radical photopolymerization, due to its fast polymerization rate, minimal temperature influence, and time-dependent properties, has been widely applied in coatings, adhesives, biomedical materials, and 3D printing. However, the formation of covalent bonds during photopolymerization shortens the distance between monomers after polymerization. Furthermore, the shrinkage stress generated by rapid cross-linking between molecules does not dissipate, leading to greater volume shrinkage than conventional thermal polymerization. This volume shrinkage reduces the precision of the photocured material, affecting its mechanical properties and even causing warping. This significantly limits its application in photocurable materials with stringent precision and performance requirements. Additionally, long-wavelength LED light sources have greater penetrability than UV LED light sources, which is beneficial for thick film curing. Therefore, reducing the volume shrinkage phenomenon in free radical long-wavelength LED photopolymerization is a crucial problem that researchers urgently need to solve. Summary of the Invention

[0003] Based on the above, the inventors of this invention have conducted extensive and in-depth research on reducing volume shrinkage, the initiation activity of disulfide compounds, and photobleaching, aiming to discover and design a novel class of disulfide compounds with reduced volume shrinkage, photoinitiation activity, and photobleaching properties. When introduced into a photocuring system, this compound exhibits advantages such as reducing volume shrinkage, initiating photopolymerization, and improving the physical and mechanical properties of materials. The inventors have discovered that disulfide compounds obtained by combining cinnamyl derivative groups with disulfide bonds can effectively initiate and reduce volume shrinkage in a 455nm wavelength LED photocuring system.

[0004] Therefore, one object of the present invention is to provide a disulfide compound containing a cinnamic yl derivative group. This group not only red-shifts the light absorption wavelength of the compound but also participates in polymerization. Thus, the disulfide compound with this structure can play a good role in initiating and reducing volume shrinkage in a 455nm wavelength LED photopolymerization system. Furthermore, due to the addition of the disulfide compound, the photocurable material also exhibits good heat resistance, abrasion resistance, and hardness.

[0005] Another object of the present invention is to provide a method for preparing the disulfide compound of the present invention. This preparation process is simple, easy to perform, uses mild conditions, and is inexpensive.

[0006] Another object of the present invention is to provide a photocurable composition comprising a disulfide compound according to the present invention.

[0007] The final objective of this invention is to provide the application of the disulfide compound of this invention in the field of LED photopolymerization.

[0008] The technical solution for achieving the above-mentioned objectives of this invention can be summarized as follows:

[0009] 1. A cinnamoyl derivative disulfide compound of general formula (Ⅰ):

[0010]

[0011] M represents

[0012] Where R1, R2, R3, R 4 Any one of the groups in R1 and R5 is taken from:

[0013] CH3O-, CH3-, H, Br,

[0014] The remaining groups in R1, R2, R3, R4, and R5 may be the same or different, and are independently selected from hydrogen, C1-C6 alkyl groups, and C1-C6 ether chains, with hydrogen, methyl, ethyl, n-propyl, and isopropyl being preferred; n ranges from 1 to 10.

[0015] 2. A method for preparing the cinnamyl derivative disulfide compound described in item 1 is as follows:

[0016] 1) Aromatic aldehyde 1, anhydrous potassium carbonate, potassium iodide and haloalkanes were dissolved in organic solvent 1 and added to a single-necked flask. The mixture was stirred evenly with a magnetic stirrer at 80°C and kept at this temperature for 12 hours. Then, organic solvent 1 was removed by rotary evaporation. The resulting mixture was dissolved in a certain amount of deionized water, extracted three times with organic solvent 2, and the organic phase was dried overnight with anhydrous sodium sulfate. Finally, organic solvent 2 was removed to obtain intermediate A.

[0017] 2) Add organic solvent 3 to a single-necked flask. Under ice-water bath conditions, add a certain amount of alkaline substance 1 to the flask and stir evenly with a magnetic stirrer. Dissolve pyruvic acid in organic solvent 3 in a certain proportion and slowly add it dropwise to the flask. Then, dissolve intermediate A or aromatic aldehyde 2 in organic solvent 3 in a certain proportion and add it dropwise to the flask at the same slow flow rate. Continue the reaction under ice-water bath conditions for 1 hour. Then, raise the system temperature to room temperature and continue stirring with a magnetic stirrer for 5 hours. Remove organic solvent 3 by vacuum distillation and dissolve the resulting yellow solid in deionized water. Use organic solvent 2 as the organic phase to repeatedly extract the unreacted raw material in the system. Then, adjust the pH of the aqueous phase to about 2-3 with dilute hydrochloric acid and extract with organic solvent 2 until the aqueous phase is clear and transparent. Finally, remove organic solvent 2 by vacuum distillation to obtain intermediate B.

[0018] 3) Dissolve intermediate B in organic solvent 4 and add it to a single-necked flask. Stir the mixture thoroughly with a magnetic stirrer under ice-water bath conditions. Dissolve oxaloyl chloride in organic solvent 4 and slowly add it to the flask at a flow rate of 2-3 drops per second. After the addition is complete, add one drop of organic solvent 5 as a catalyst. Keep the reaction at an ice-water bath for 0.5 h. Remove organic solvent 4 and excess oxaloyl chloride by vacuum distillation using a rotary evaporator to obtain intermediate C. Add an aromatic disulfide compound with active hydrogen and basic substance 2 to a single-necked flask and add a certain amount of organic solvent 4. Stir the mixture thoroughly with a magnetic stirrer under ice-water bath conditions. Dissolve intermediate C in organic solvent 4 and slowly add it to the flask at a flow rate of 2-3 drops per second. Keep the reaction at an ice-water bath for 4 h. After the reaction is complete, remove insoluble substances using a vacuum filtration device and remove organic solvent 4 using a rotary evaporator. Separate and purify the obtained solid mixture by silica gel column chromatography to obtain cinnamyl derivative disulfide compound.

[0019] 3. The method according to item 2, characterized in that: organic solvent 1 is selected from anhydrous acetonitrile, ethyl acetate, dichloromethane, tetrahydrofuran, N,N-dimethylformamide, toluene, xylene, preferably anhydrous acetonitrile; organic solvent 2 is selected from ethyl acetate, dichloromethane, toluene, xylene, preferably ethyl acetate; organic solvent 3 is selected from anhydrous ethanol, anhydrous methanol, isopropanol, preferably anhydrous ethanol; organic solvent 4 is selected from tetrahydrofuran, ethyl acetate, toluene, xylene, anhydrous acetonitrile, preferably tetrahydrofuran; and organic solvent 5 is N,N-dimethylformamide.

[0020] 4. The method according to item 2, characterized in that the aromatic aldehyde 1 is selected from 4-hydroxybenzaldehyde, 3-hydroxybenzaldehyde, 2-hydroxybenzaldehyde, 2,4-dihydroxybenzaldehyde, 3,4-dihydroxybenzaldehyde, preferably 4-hydroxybenzaldehyde; the aromatic aldehyde 2 is p-methoxybenzaldehyde, p-methylbenzaldehyde, benzaldehyde, p-bromobenzaldehyde; the haloalkane is 1-bromohexane, 6-bromo-1-hexene, 1-bromoisopentane, 1-bromo-2-(2-methoxyethoxy)ethane.

[0021] 5. The method according to item 2, characterized in that: alkaline substance 1 is selected from potassium hydroxide, sodium hydroxide, magnesium hydroxide, sodium hydride, preferably potassium hydroxide; alkaline substance 2 is selected from triethylamine, pyridine, imidazole, diisopropylamine, 1,8-diazabicyclo[5.4.0]undec-7-ene, preferably triethylamine and imidazole; the molar ratio of alkaline substance 1 to pyruvic acid is 1.5:1 to 2:1, preferably 1.5:1; the molar ratio of intermediate A or aromatic aldehyde 2 to pyruvic acid is 1:1 to 1:1.5, preferably 1:1.5; the molar ratio of intermediate C to an aromatic disulfide compound with active hydrogen is 2.2:1 to 2.5:1, preferably 2.2:1.

[0022] 6. A composition cured by free radical photopolymerization, characterized in that it comprises the cinnamic yl derivative disulfide compound described in item 1.

[0023] 7. The composition according to item 6, characterized in that the composition comprises 1% to 10% of the disulfide compound and 90% to 99% of the photoreactive resin or active monomer; or comprises 1% to 8% of the cinnamic yl derivative disulfide compound, 1% to 5% of the photoinitiator and 87% to 98% of the photoreactive resin or active monomer, based on the total weight of the composition.

[0024] 8. The composition according to item 7, characterized in that the photoreactive resin is selected from one or more of epoxy (meth)acrylate resin, polyurethane (meth)acrylate resin, polyester (meth)acrylate resin, polyether (meth)acrylate resin, and acrylated poly (meth)acrylate resin; the active monomer is one or more of monofunctional, difunctional, or polyfunctional (meth)acrylate monomers; and the photoinitiator is selected from one or more of free radical photoinitiators.

[0025] 9. The application of the cinnamyl derivative disulfide compound described in item 1 in the field of LED photopolymerization.

[0026] In the following description of the invention, unless otherwise expressly stated, all numerical values ​​in this application are to be regarded as being modified by the word "approximately". However, the inventors have reported the numerical values ​​in the embodiments as accurately as possible, although these numerical values ​​inevitably include a certain degree of error.

[0027] In this application, unless explicitly excluded, specific or preferred embodiments of the invention can be combined. Furthermore, the elements of the embodiments of this application are specific preferred selections of their corresponding higher-level technical features. If a higher-level technical feature can be combined with other higher-level features, then the elements of the embodiments, i.e., the specific preferred selections, can also be combined with those other higher-level features. These combinations should be considered part of the original description of this application.

[0028] The disulfide compound described in this invention can initiate the polymerization of methacrylic acid monomer resin under 455nm LED illumination while simultaneously reducing the volume shrinkage of the photocurable material. The mechanism is as follows: Figure 1 As shown, under light irradiation, the disulfide compound molecules undergo SS bond breakage, generating aryl sulfide radicals. Then, some of these aryl sulfide radicals attack the double bonds to generate primary carbon radicals, which rapidly initiate chain polymerization of the monomers. Other aryl sulfide radicals tend to recombine and revert to disulfide bonds. During photopolymerization, the disulfide bonds continuously repeat the reversible "break-restore" reaction. Accompanying this reversible process, the polymer network continuously undergoes a "contraction-expansion-contraction" volume adjustment process, thereby macroscopically reducing the volume shrinkage phenomenon of the photopolymer material.

[0029] The beneficial effects of this invention are as follows: compared with traditional methods for reducing volume shrinkage, it is simpler and more effective, and can be applied to the field of long-wavelength (455nm) LED photopolymerization. It not only effectively reduces the volume shrinkage of photopolymer materials, but also exhibits good photopolymerization initiation ability in the long-wavelength band and demonstrates good photobleaching properties. Furthermore, the addition of disulfide compounds in this invention significantly improves the thermal stability, abrasion resistance, and hardness of photocurable materials. This invention has important theoretical significance and potential application value for the development of LED photopolymerization technology and the expansion of the application fields of disulfide compounds.

[0030] Source of raw materials

[0031] Table 1. Main Reagents and Manufacturers

[0032]

[0033] Attached Figure Description

[0034] Figure 1 This invention provides an initiation mechanism diagram of disulfide compounds that have the ability to initiate and reduce volume shrinkage in LED photopolymerization systems.

[0035] Figure 2These are the UV-Vis absorption spectra of the four disulfide compounds prepared in Examples 1, 2, 3, and 4.

[0036] Figure 3 These are the UV-Vis absorption spectra of the four disulfide compounds prepared in Examples 5, 6, 7, and 8.

[0037] Figure 4 The double bond conversion spectra of the four disulfide compounds prepared in Examples 1, 2, 3 and 4 under 455nm LED light source irradiation for the polymerization of complex monomers.

[0038] Figure 5 The double bond conversion spectra of the four disulfide compounds prepared in Examples 5, 6, 7 and 8 under 455nm LED light source irradiation for the polymerization of complex monomers.

[0039] Figure 6 The double bond conversion rate spectra of the four disulfide compounds prepared in Examples 1, 2, 3 and 4 under 455nm LED light source irradiation for the polymerization of complex monomers.

[0040] Figure 7 The double bond conversion rate spectra of the four disulfide compounds prepared in Examples 5, 6, 7 and 8 under 455nm LED light source irradiation for the polymerization of complex monomers.

[0041] Figure 8 The double bond conversion spectra of the disulfide compounds prepared in Example 5, with different amounts added, were irradiated by a 455nm LED light source.

[0042] Figure 9 The image shows the double bond conversion rate spectra of the disulfide compounds prepared in Example 5 with different amounts added under 455nm LED light source irradiation.

[0043] Figure 10 This is a graph showing the volume shrinkage rate of the complex monomers induced by adding different amounts of the disulfide compound prepared in Example 5 under 455nm LED light source irradiation;

[0044] Figure 11 The thermogravimetric curves are those of the cured films with different amounts of disulfide compounds added, prepared in Example 5.

[0045] Figure 12 The Shore hardness of the cured films with different amounts of disulfide compounds added, prepared in Example 5;

[0046] Figure 13 The photobleaching properties of the disulfide compound prepared in Example 1;

[0047] Example 1

[0048] The preparation of O-BSCF, a disulfide compound with the ability to initiate and reduce volume shrinkage in LED photopolymerization, is described below:

[0049]

[0050] Take 50 mL of anhydrous ethanol solution and add it to a 250 mL single-necked flask. Add potassium hydroxide (1.68 g, 30 mmol) to the flask under ice-water bath conditions and stir with a magnetic stirrer until homogeneous. Dissolve pyruvate (1.76 g, 20 mmol) in 15 mL of anhydrous ethanol solution and slowly add it dropwise to the flask. Then, dissolve p-methoxybenzaldehyde (3.04 g, 20 mmol) in 15 mL of anhydrous ethanol solution and add it dropwise to the flask at the same slow flow rate. Continue the reaction under ice-water bath conditions for 1 h, then raise the system temperature to room temperature and continue stirring with a magnetic stirrer for 5 h. Remove the anhydrous ethanol by vacuum distillation and dissolve the resulting yellow solid in deionized water. Use ethyl acetate as the organic phase to repeatedly extract unreacted raw materials from the system. Then, adjust the pH of the aqueous phase to approximately 2-3 with dilute hydrochloric acid and extract with ethyl acetate until the aqueous phase is clear and transparent. Finally, remove the solvent by vacuum distillation to obtain intermediate B (2.34 g, 65%).

[0051] The proton NMR data of intermediate B are as follows: 1 H NMR (400MHz, DMSO-d6) δ7.83–7.75(m,2H),7.71(d,J=16.2Hz,1H),7.15(d,J=16.2Hz,1H),7.07–6.98(m,2H),3.83(s,3H).

[0052] The carbon spectrum data of intermediate B are as follows: 13 C NMR (100MHz, DMSO-d6) δ186.52,165.28,162.59,148.14,131.67,126.91,119.52,115.11,55.93.

[0053] Take 20 mL of tetrahydrofuran solution and add it to a 100 mL single-necked flask. Add the synthesized intermediate B (2.06 g, 10 mmol) to the flask and stir thoroughly with a magnetic stirrer. Dissolve oxalyl chloride (1.32 g, 15 mmol) in 10 mL of tetrahydrofuran solution under ice-water bath conditions and add it dropwise to the flask at a slow flow rate. After the addition is complete, add one drop of DMF as a catalyst. Incubate the reaction under ice-water bath conditions for 0.5 h. Remove tetrahydrofuran and excess oxalyl chloride by rotary evaporation under reduced pressure to obtain intermediate C. Dissolve 2,2'-dithiodiphenylamine (1.24 g, 5 mmol) and triethylamine (1.01 g, 10 mmol) in 20 mL of tetrahydrofuran solution and add it to a 100 mL single-necked flask. Stir thoroughly with a magnetic stirrer under ice-water bath conditions. Dissolve intermediate C in 10 mL of tetrahydrofuran solution and add it dropwise to the reaction system. Continue stirring the reaction with a magnetic stirrer for 4 hours. Then remove insoluble substances using a vacuum filtration device, remove tetrahydrofuran by low-pressure distillation of the obtained organic phase, and purify the mixture by column chromatography (PE:EA = 20:1, volume ratio). O-BSCF is a yellow solid product (1.62 g, yield 52%, melting point: 141-143 °C).

[0054] The proton spectrum data of O-BSCF are 1 H NMR (400MHz, CDCl3) δ8.46 (dd, J=8.3, 1.3Hz, 1H), 7.96 (d, J=16.0Hz, 1H), 7.77–7.63 (m, 3H), 7.45–7.33 (m, 2H), 7.05–6.96 (m, 3H), 3.89 (s, 3H).

[0055] The carbon spectral data of O-BSCF are 13 C NMR (100MHz, CDCl3) δ184.20,162.66,158.90,148.47,138.82,136.86,131.96,131.32,127.29,125.05,124.33,120.25,115.39,114.63,55.52.

[0056] Example 2

[0057] The preparation of Me-BSCF, a disulfide compound with the ability to initiate and reduce volume shrinkage in LED photopolymerization, is described below:

[0058]

[0059] Take 50 mL of anhydrous ethanol solution and add it to a 250 mL single-necked flask. Add potassium hydroxide (1.68 g, 30 mmol) to the flask under ice-water bath conditions and stir with a magnetic stirrer until homogeneous. Dissolve pyruvate (1.76 g, 20 mmol) in 15 mL of anhydrous ethanol solution and slowly add it dropwise to the flask. Then dissolve p-methylbenzaldehyde (2.40 g, 20 mmol) in 15 mL of anhydrous ethanol solution and add it dropwise to the flask at a slow flow rate. Continue the reaction under ice-water bath conditions for 1 h, then raise the system temperature to room temperature and continue stirring with a magnetic stirrer for 5 h. Remove the anhydrous ethanol by vacuum distillation and dissolve the resulting yellow solid in deionized water. Use ethyl acetate as the organic phase to repeatedly extract unreacted raw materials from the system. Then adjust the pH of the aqueous phase to approximately 2-3 with dilute hydrochloric acid and extract the organic matter in the aqueous phase with ethyl acetate until the aqueous phase is clear and transparent. Finally, remove the solvent by vacuum distillation to obtain intermediate B (2.24 g, 59%).

[0060] The proton NMR data of intermediate B are as follows: 1 H NMR (400MHz, DMSO-d6)7.76–7.66(m,3H),7.28(d,J=7.9Hz,2H),7.23(d,J=16.3Hz,1H),2.35(s,3H).

[0061] The carbon spectrum data of the intermediate are 13 C NMR (100MHz, DMSO-d6) δ186.59,165.06,148.11,142.36,131.59,130.22,129.61,121.00,21.59.

[0062] Take 20 mL of tetrahydrofuran solution and add it to a 100 mL single-necked flask. Add the synthesized intermediate B (1.90 g, 10 mmol) to the flask and stir thoroughly with a magnetic stirrer. Dissolve oxalyl chloride (1.32 g, 15 mmol) in 10 mL of tetrahydrofuran solution under ice-water bath conditions and add it dropwise to the flask at a slow flow rate. After the addition is complete, add one drop of DMF as a catalyst. Incubate the reaction under ice-water bath conditions for 0.5 h. Remove tetrahydrofuran and excess oxalyl chloride by rotary evaporation under reduced pressure to obtain intermediate C. Dissolve 2,2'-dithiodiphenylamine (1.24 g, 5 mmol) and triethylamine (1.01 g, 10 mmol) in 20 mL of tetrahydrofuran solution and add it to a 100 mL single-necked flask. Stir thoroughly with a magnetic stirrer under ice-water bath conditions. Dissolve intermediate C in 10 mL of tetrahydrofuran solution and add it dropwise to the reaction system. Continue stirring the reaction with a magnetic stirrer for 4 hours. Then remove insoluble substances using a vacuum filtration device, remove tetrahydrofuran by low-pressure distillation of the obtained organic phase, and purify the mixture by silica gel column chromatography (PE:EA = 15:1, volume ratio). Me-BSCF is a yellow solid product (1.63 g, yield 55%, melting point: 159-161℃).

[0063] The 1H NMR data of Me-BSCF are 1 H NMR (400MHz, CDCl3) δ8.46(dd,J=8.3,1.3Hz,1H),7.99(d,J=16.1Hz,1H),7.79(d,J=16.0Hz,1H),7.68–7.62(m,2H ),7.43(dd,J=7.7,1.5Hz,1H),7.41–7.33(m,1H),7.29(d,J=8.0Hz,2H),7.04(td,J=7.6,1.4Hz,1H),2.44(s,3H).

[0064] The carbon spectral data of Me-BSCF are 13 C NMR (100MHz, CDCl3) δ184.43,158.70,148.72,142.51,138.78,136.89,131.99,131.76,129.89,129.38,125.13,124.35,120.25,116.79,21.70.

[0065] Example 3

[0066] The preparation of BSCF, a disulfide compound with the ability to initiate and reduce volume shrinkage in LED photopolymerization, is described below:

[0067]

[0068] Take 50 mL of anhydrous ethanol solution and add it to a 250 mL single-necked flask. Add potassium hydroxide (1.68 g, 30 mmol) to the flask under ice-water bath conditions and stir with a magnetic stirrer until homogeneous. Dissolve pyruvic acid (1.76 g, 20 mmol) in 15 mL of anhydrous ethanol solution and slowly add it dropwise to the flask. Then, dissolve benzaldehyde (2.20 g, 20 mmol) in 15 mL of anhydrous ethanol solution and add it dropwise to the flask at a slow flow rate. Continue the reaction under ice-water bath conditions for 1 h, then raise the system temperature to room temperature and continue stirring with a magnetic stirrer for 5 h. Remove the anhydrous ethanol by vacuum distillation and dissolve the resulting yellow solid in deionized water. Use ethyl acetate as the organic phase to repeatedly extract unreacted raw materials from the system. Then, adjust the pH of the aqueous phase to approximately 2-3 with dilute hydrochloric acid and extract with ethyl acetate until the aqueous phase is clear and transparent. Finally, remove the solvent by vacuum distillation to obtain intermediate B (2.18 g, 62%).

[0069] Proton NMR data of intermediate B 1 H NMR (400MHz, DMSO-d6) δ7.82–7.71(m,2H),7.76(d,J=16.3Hz,1H),7.52–7.40(m,3H),7.30(d,J=16.3Hz,1H).

[0070] Carbon spectrum data of intermediate B 13 C NMR (100MHz, DMSO-d6) δ186.50,164.89,147.89,134.27,131.95,129.54,129.51,121.98.

[0071] Take 20 mL of tetrahydrofuran solution and add it to a 100 mL single-necked flask. Add the synthesized intermediate B (1.76 g, 10 mmol) to the flask and stir thoroughly with a magnetic stirrer. Dissolve oxalyl chloride (1.32 g, 15 mmol) in 10 mL of tetrahydrofuran solution under ice-water bath conditions and add it dropwise to the flask at a slow flow rate. After the addition is complete, add one drop of DMF as a catalyst, and incubate the reaction under ice-water bath conditions for 0.5 h. Remove tetrahydrofuran and excess oxalyl chloride using a rotary evaporator to obtain intermediate C. Dissolve 2,2'-dithiodiphenylamine (1.24 g, 5 mmol) and triethylamine (1.01 g, 10 mmol) in 20 mL of tetrahydrofuran solution and add it to a 100 mL single-necked flask. Stir thoroughly with a magnetic stirrer under ice-water bath conditions. Dissolve intermediate C in 10 mL of tetrahydrofuran solution and add it dropwise to the reaction system. Continue stirring the reaction with a magnetic stirrer for 4 hours. Then remove insoluble substances using a vacuum filtration device, remove tetrahydrofuran by low-pressure distillation of the obtained organic phase, and purify the mixture by silica gel column chromatography (PE:EA = 20:1, volume ratio). BSCF is a yellow solid product (1.63 g, yield 58%, melting point: 134-136℃).

[0072] The proton spectrum data of BSCF are 1 H NMR(400MHz, CDCl3) δ8.47(dd,J=8.3,1.3Hz,1H),8.01(d,J=16.1Hz,1H),7.84(d,J=16.1Hz,1H) ,7.79–7.71(m,2H),7.55–7.40(m,4H),7.37(td,J=7.8,1.6Hz,1H),7.04(td,J=7.6,1.3Hz,1H).

[0073] The carbon spectral data of BSCF are 13 C NMR (100MHz, CDCl3) δ184.47,158.53,148.60,138.75,136.93,134.40,132.03,131.68,129.31,129.13,125.20,124.36,120.25,117.80.

[0074] Example 4

[0075] The preparation of Br-BSCF, a disulfide compound with the ability to initiate and reduce volume shrinkage in LED photopolymerization, is described below:

[0076]

[0077] Take 50 mL of anhydrous ethanol solution and add it to a 250 mL single-necked flask. Add potassium hydroxide (1.68 g, 30 mmol) to the flask under ice-water bath conditions and stir with a magnetic stirrer until homogeneous. Dissolve pyruvate (1.76 g, 20 mmol) in 15 mL of anhydrous ethanol solution and slowly add it dropwise to the flask. Then, dissolve p-bromobenzaldehyde (3.80 g, 20 mmol) in 15 mL of anhydrous ethanol solution and add it dropwise to the flask at a slow flow rate. Continue the reaction under ice-water bath conditions for 1 h, then raise the system temperature to room temperature and continue stirring with a magnetic stirrer for 5 h. Remove the anhydrous ethanol by vacuum distillation and dissolve the resulting yellow solid in deionized water. Use ethyl acetate as the organic phase to repeatedly extract unreacted raw materials from the system. Then, adjust the pH of the aqueous phase to approximately 2-3 with dilute hydrochloric acid and extract the organic matter from the aqueous phase with ethyl acetate until the aqueous phase is clear and transparent. Finally, remove the solvent by vacuum distillation to obtain intermediate B (2.80 g, 55%).

[0078] The proton NMR data of intermediate B are as follows: 1 H NMR (400MHz, DMSO-d6) δ7.75–7.66 (m, 3H), 7.64–7.57 (m, 2H), 7.31 (d, J = 16.4Hz, 1H).

[0079] The carbon spectrum data of intermediate B are as follows: 13 C NMR (100MHz, DMSO-d6) δ186.20,164.64,146.34,133.54,132.50,131.30,125.45,122.59.

[0080] Take 20 mL of tetrahydrofuran solution and add it to a 100 mL single-necked flask. Add the synthesized intermediate B (2.55 g, 10 mmol) to the flask and stir thoroughly with a magnetic stirrer. Dissolve oxalyl chloride (1.32 g, 15 mmol) in 10 mL of tetrahydrofuran solution under ice-water bath conditions and add it dropwise to the flask at a slow flow rate. After the addition is complete, add one drop of DMF as a catalyst and incubate the reaction under ice-water bath conditions for 0.5 h. Remove the tetrahydrofuran using a rotary evaporator to obtain intermediate C. Dissolve 2,2'-dithiodiphenylamine (1.24 g, 5 mmol) and triethylamine (1.01 g, 10 mmol) in 20 mL of tetrahydrofuran solution and add it to a 100 mL single-necked flask. Stir thoroughly with a magnetic stirrer under ice-water bath conditions. Dissolve intermediate C in 10 mL of tetrahydrofuran solution and add it dropwise to the reaction system. Continue stirring with a magnetic stirrer for 4 h. Then, the insoluble substances were removed by vacuum filtration, and the obtained organic phase was distilled at low pressure to remove tetrahydrofuran. The mixture was separated and purified by recrystallization. The volume ratio of the solvents petroleum ether (PE) and ethyl acetate (EA) was 1:1. Br-BSCF was a yellow solid product (2.45 g, yield 68%, melting point: 202-204 °C).

[0081] The proton NMR data of Br-BSCF are 1 H NMR (400MHz, CDCl3) δ8.44 (dd, J=8.3, 1.3Hz, 1H), 7.92 (d, J=16.1Hz, 1H), 7.81 (d, J=16.1Hz,1H),7.66–7.52(m,4H),7.47–7.33(m,2H),7.05(td,J=7.6,1.3Hz,1H).

[0082] The carbon spectrum data of Br-BSCF are as follows 13 C NMR (100MHz, CDCl3) δ184.38,158.37,147.06,138.65,136.93,133.26,132.44,132.03,130.52,126.21,125.26,124.36,120.26,118.34.

[0083] Example 5

[0084] The preparation of Mp-BSCF, a disulfide compound with the ability to initiate and reduce volume shrinkage in LED photopolymerization, is described below:

[0085]

[0086] p-Hydroxybenzaldehyde (1.22 g, 10 mmol), anhydrous potassium carbonate (2.07 g, 15 mmol), potassium iodide (0.02 g, 0.1 mmol), and 1-bromo-2-(2-methoxyethoxy)ethane (2.75 g, 15 mmol) were dissolved in 30 mL of acetonitrile solution and added to a 100 mL single-necked flask. The mixture was stirred at 80 °C with a magnetic stirrer for 12 h. The acetonitrile solution was then removed by rotary evaporation. The resulting white solid mixture was dissolved in 20 mL of deionized water, extracted three times with ethyl acetate, and the organic phase was dried overnight with anhydrous sodium sulfate. Finally, the ethyl acetate was removed to obtain intermediate A (2.06 g, 92%).

[0087] The proton NMR data of intermediate A are as follows: 1 H NMR(400MHz, CDCl3)δ9.81(s,1H),7.79–7.71(m,2H),7.00–6.91(m,2H),4.19–4.12(m,2 H),3.86–3.79(m,2H),3.78–3.55(m,2H),3.50(ddt,J=8.9,6.2,3.4Hz,2H),3.32(s,3H).

[0088] The carbon spectrum data of intermediate A are as follows: 13 C NMR (100MHz, CDCl3) δ190.57,163.77,131.79,129.99,114.78,71.83,70.71,69.38,67.67,60.18.

[0089] Take 50 mL of anhydrous ethanol solution and add it to a 250 mL single-necked flask. Add potassium hydroxide (1.68 g, 30 mmol) to the flask under ice-water bath conditions and stir thoroughly with a magnetic stirrer. Dissolve pyruvate (1.76 g, 20 mmol) in 15 mL of anhydrous ethanol solution and slowly add it dropwise to the flask. Then dissolve intermediate A (4.48 g, 20 mmol) in 15 mL of anhydrous ethanol solution and add it dropwise to the flask at the same slow flow rate. Incubate the reaction under ice-water bath conditions for 1 h, remove the ice-water bath, and raise the system temperature to room temperature to continue the reaction for 5 h. Remove the anhydrous ethanol using a rotary evaporator. Dissolve the resulting carboxylate in deionized water and repeatedly extract with ethyl acetate to remove unreacted starting material. Adjust the pH of the aqueous phase to approximately 2-3 using dilute hydrochloric acid. Finally, extract the organic matter from the aqueous phase with ethyl acetate until the aqueous phase is clear and transparent. Dry the organic phase overnight with anhydrous sodium sulfate. Finally, remove ethyl acetate to obtain intermediate B (3.64 g, 62%).

[0090] The proton NMR data of intermediate B are as follows: 1H NMR(400MHz, DMSO-d6)δ7.79–7.66(m,3H),7.14(d,J=16.2Hz,1H),7.05–6.92(m,2H),4 .20–4.11(m,2H),3.79–3.69(m,2H),3.63–3.52(m,2H),3.47–3.41(m,2H),3.23(s,3H).

[0091] The carbon spectrum data of intermediate B are as follows: 13 C NMR (100MHz, DMSO-d6) δ186.41,165.23,161.84,148.08,131.62,126.93,119.48,115.53,71.71,70.18,69.20,67.91,58.47.

[0092] Intermediate B (2.94 g, 10 mmol) was dissolved in 20 mL of tetrahydrofuran solution and added to a 100 mL single-necked flask. The mixture was stirred thoroughly with a magnetic stirrer under ice-water bath conditions. Oxaloyl chloride (1.32 g, 15 mmol) was dissolved in 10 mL of tetrahydrofuran solution and slowly added dropwise to the flask at a flow rate of 2-3 drops per second. After the addition was complete, one drop of DMF was added as a catalyst, and the reaction was maintained at an ice-water bath for 0.5 h. The tetrahydrofuran and excess oxaloyl chloride were removed by rotary evaporation under reduced pressure to obtain intermediate C. Using 20 mL of tetrahydrofuran as a solvent, 2,2'-dithiodiphenylamine (1.24 g, 5 mmol) and triethylamine (1.01 g, 10 mmol) were added to a 100 mL single-necked flask and stirred thoroughly with a magnetic stirrer under ice-water bath conditions. Intermediate C was dissolved in 10 mL of tetrahydrofuran solution and slowly added dropwise to the flask at a flow rate of 2-3 drops per second. The reaction was maintained at this temperature for 4 hours. After the reaction was completed, insoluble substances were removed by vacuum filtration, and tetrahydrofuran was removed by rotary evaporation. The resulting solid mixture was purified by silica gel column chromatography, with the eluents petroleum ether (PE) and ethyl acetate (EA) in a volume ratio of 20:1. Mp-BSCF was a yellow solid product (1.80 g, yield 45%, melting point: 81-83 °C).

[0093] The proton spectrum data of Mp-BSCF are 1H NMR(400MHz, CDCl3)δ10.01(s,1H),8.45(dd,J=8.3,1.3Hz,1H),7.96(d,J=16.0Hz,1H),7.74–7.65(m,3H),7.45–7.33(m,2H), 7.07–6.96(m,3H),4.23(dd,J=5.7,3.9Hz,2H),3.91(dd,J=5.7,4.0Hz,2H),3.80–3.72(m,2H),3.64–3.56(m,2H),3.42(s,3H).

[0094] The carbon spectral data of Mp-BSCF are 13 C NMR (100MHz, CDCl3) δ184.18,161.87,158.88,148.45,138.81,136.85,131.96,131.28 ,127.41,125.06,124.32,120.24,115.43,115.21,71.95,70.83,69.58,67.65,59.11.

[0095] Example 6

[0096] The preparation of Ha-BSCF, a disulfide compound with the ability to initiate and reduce volume shrinkage in LED photopolymerization, is described below:

[0097]

[0098] p-Hydroxybenzaldehyde (1.22 g, 10 mmol), anhydrous potassium carbonate (2.07 g, 15 mmol), potassium iodide (0.02 g, 0.1 mmol), and 1-bromohexane (2.48 g, 15 mmol) were dissolved in 30 mL of acetonitrile solution and added to a 100 mL single-necked flask. The mixture was stirred at 80 °C with a magnetic stirrer for 8 h. The acetonitrile solution was then removed by rotary evaporation. The resulting white solid mixture was dissolved in 20 mL of deionized water, extracted three times with ethyl acetate, and the organic phase was dried overnight with anhydrous sodium sulfate. Finally, the ethyl acetate was removed to obtain intermediate A (1.81 g, 88%).

[0099] The proton NMR data of intermediate A are as follows: 1H NMR (400MHz, CDCl3) δ9.87 (s, 1H), 7.86–7.77 (m, 2H), 7.02–6.94 (m, 2H), 4.03 (t, J = 6. 6Hz,2H),1.80(m,2H),1.52–1.41(m,2H),1.34(m,4H),0.90(t,J=7.7,6.1,2.4Hz,3H).

[0100] The carbon spectrum data of intermediate A are as follows: 13 C NMR (100MHz, CDCl3) δ190.33,164.11,131.75,129.70,114.60,68.25,31.44,28.93,25.54,22.48,13.89.

[0101] Take 50 mL of anhydrous ethanol solution and add it to a 250 mL single-necked flask. Add potassium hydroxide (1.68 g, 30 mmol) to the flask under ice-water bath conditions and stir thoroughly with a magnetic stirrer. Dissolve pyruvate (1.76 g, 20 mmol) in 15 mL of anhydrous ethanol solution and slowly add it dropwise to the flask. Then dissolve intermediate A (4.12 g, 20 mmol) in 15 mL of anhydrous ethanol solution and add it dropwise to the flask at the same slow flow rate. Continue the reaction under ice-water bath conditions for 1 h. Remove the ice-water bath and raise the system temperature to room temperature, continuing the reaction for another 5 h. Remove the anhydrous ethanol using a rotary evaporator. Dissolve the resulting carboxylate in deionized water and repeatedly extract with ethyl acetate to remove unreacted starting material. Adjust the pH of the aqueous phase to approximately 2-3 using dilute hydrochloric acid. Finally, extract the organic matter from the aqueous phase with ethyl acetate until the aqueous phase is clear and transparent. Dry the organic phase overnight with anhydrous sodium sulfate. Finally, remove ethyl acetate to obtain intermediate B (3.25 g, 59%).

[0102] The proton NMR data of intermediate B are as follows: 1 H NMR (400MHz, DMSO-d6) δ7.77–7.67(m,3H),7.14(d,J=16.2Hz,1H),7.01–6.93(m,2H ),3.98(q,J=6.2Hz,2H),1.67(m,2H),1.37(m,2H),1.26(m,4H),0.88–0.79(t,3H).

[0103] The carbon spectrum data of intermediate B are as follows: 13 C NMR (100MHz, DMSO-d6) δ186.26,165.20,162.08,148.08,131.59,126.74,119.30,115.43,68.23,31.45,28.98,25.59,22.52,14.28.

[0104] Intermediate B (2.76 g, 10 mmol) was dissolved in 20 mL of tetrahydrofuran solution and added to a 100 mL single-necked flask. The mixture was stirred thoroughly with a magnetic stirrer under ice-water bath conditions. Oxaloyl chloride (1.32 g, 15 mmol) was dissolved in 10 mL of tetrahydrofuran solution and slowly added dropwise to the flask at a flow rate of 2-3 drops per second. After the addition was complete, one drop of DMF was added as a catalyst, and the reaction was maintained at an ice-water bath for 0.5 h. The tetrahydrofuran and excess oxaloyl chloride were removed by rotary evaporation under reduced pressure to obtain intermediate C. Using 20 mL of tetrahydrofuran as a solvent, 2,2'-dithiodiphenylamine (1.24 g, 5 mmol) and triethylamine (1.01 g, 10 mmol) were added to a 100 mL single-necked flask and stirred thoroughly with a magnetic stirrer under ice-water bath conditions. Intermediate C was dissolved in 10 mL of tetrahydrofuran solution and slowly added dropwise to the flask at a flow rate of 2-3 drops per second. The reaction was maintained at this temperature for 4 hours. After the reaction was completed, insoluble substances were removed by vacuum filtration, and tetrahydrofuran was removed by rotary evaporation. The resulting solid mixture was purified by silica gel column chromatography, with the eluent being petroleum ether (PE) and ethyl acetate (EA) in a volume ratio of 15:1. Ha-BSCF was a yellow solid product (1.99 g, yield 52%, melting point: 81-83 °C).

[0105] The 1H NMR data of Ha-BSCF are 1 H NMR (400MHz, CDCl3) δ10.03(s,1H),8.47(dd,J=8.3,1.3Hz,1H),7.97(d,J=16.0Hz,1H),7.75–7.65(m,3H),7.45–7.33(m,2H),7.0 3(td,J=7.6,1.4Hz,1H),7.02–6.88(m,2H),4.05(t,J=6.6Hz,2H),1.83(m,2H),1.56–1.44(m,2H),1.38(m,4H),1.04–0.88(m,3H).

[0106] The carbon spectral data of Ha-BSCF are 13 C NMR (100MHz, CDCl3) δ184.17,162.35,158.95,148.61,138.84,136.85,131.96,131.35,12 7.04,125.05,124.33,120.25,115.18,115.10,68.33,31.56,29.10,25.68,22.61,14.05.

[0107] Example 7

[0108] The preparation of He-BSCF, a disulfide compound with the ability to initiate and reduce volume shrinkage in LED photopolymerization, is described below:

[0109]

[0110] p-Hydroxybenzaldehyde (1.22 g, 10 mmol), anhydrous potassium carbonate (2.07 g, 15 mmol), potassium iodide (0.02 g, 0.1 mmol), and 6-bromo-1-hexene (2.45 g, 15 mmol) were dissolved in 30 mL of acetonitrile solution and added to a 100 mL single-necked flask. The mixture was stirred at 80 °C with a magnetic stirrer for 17 h. The acetonitrile solution was then removed by rotary evaporation. The resulting white solid mixture was dissolved in 20 mL of deionized water, extracted three times with ethyl acetate, and the organic phase was dried overnight with anhydrous sodium sulfate. Finally, the ethyl acetate was removed to obtain intermediate A (1.88 g, 92%).

[0111] The proton NMR data of intermediate A are as follows: 1 H NMR (400MHz, CDCl3) δ9.89 (s, 1H), 7.88–7.80 (m, 2H), 7.04–6.96 (m, 2H), 5.84 (ddt, J=16.9, 10.1, 6.7Hz, 1H ),5.11–5.00(m,1H),5.04–4.95(m,1H),4.06(t,J=6.4Hz,2H),2.22–2.05(m,2H),1.85(m,2H),1.60(m,2H).

[0112] The carbon spectrum data of intermediate A are as follows: 13 C NMR (100MHz, CDCl3) δ190.80,164.20,138.31,131.99,129.79,114.93,114.75,68.19,33.35,28.48,25.22.

[0113] Take 50 mL of anhydrous ethanol solution and add it to a 250 mL single-necked flask. Add potassium hydroxide (1.68 g, 30 mmol) to the flask under ice-water bath conditions and stir thoroughly with a magnetic stirrer. Dissolve pyruvate (1.76 g, 20 mmol) in 15 mL of anhydrous ethanol solution and slowly add it dropwise to the flask. Then dissolve intermediate A (4.08 g, 20 mmol) in 15 mL of anhydrous ethanol solution and add it dropwise to the flask at the same slow flow rate. Continue the reaction under ice-water bath conditions for 1 h. Remove the ice-water bath and raise the system temperature to room temperature, continuing the reaction for another 5 h. Remove the anhydrous ethanol using a rotary evaporator. Dissolve the resulting carboxylate in deionized water and repeatedly extract with ethyl acetate to remove unreacted starting material. Adjust the pH of the aqueous phase to approximately 2-3 using dilute hydrochloric acid. Finally, extract the organic matter from the aqueous phase with ethyl acetate until the aqueous phase is clear and transparent. Dry the organic phase overnight with anhydrous sodium sulfate. Finally, remove ethyl acetate to obtain intermediate B (3.02 g, 55%).

[0114] The proton NMR data of intermediate B are as follows: 1 H NMR(400MHz, DMSO-d6)δ7.82–7.64(m,3H),7.14(d,J=16.2Hz,1H),7.04–6.96(m,2H),5.83(ddt,J=16.9,10.2, 6.6,3.6Hz,1H),5.10–4.87(m,2H),4.11–3.99(m,2H),2.18–2.01(m,2H),1.84–1.66(m,2H),1.57–1.43(m,2H).

[0115] The carbon spectrum data of intermediate B are as follows: 13 C NMR (100MHz, DMSO-d6) δ186.49,165.29,162.06,148.19,138.97,131.70,126.78,119.41,115.53,115.44,68.09,33.28,28.47,25.13.

[0116] Intermediate B (2.74 g, 10 mmol) was dissolved in 20 mL of tetrahydrofuran solution and added to a 100 mL single-necked flask. The mixture was stirred thoroughly with a magnetic stirrer under ice-water bath conditions. Oxaloyl chloride (1.32 g, 15 mmol) was dissolved in 10 mL of tetrahydrofuran solution and slowly added dropwise to the flask at a flow rate of 2-3 drops per second. After the addition was complete, one drop of DMF was added as a catalyst, and the reaction was maintained at an ice-water bath for 0.5 h. Tetrahydrofuran and excess oxaloyl chloride were removed by rotary evaporation under reduced pressure to obtain intermediate C. Using 20 mL of tetrahydrofuran as a solvent, 2,2'-dithiodiphenylamine (1.24 g, 5 mmol) and triethylamine (1.01 g, 10 mmol) were added to a 100 mL single-necked flask and stirred thoroughly with a magnetic stirrer under ice-water bath conditions. Intermediate C was dissolved in 10 mL of tetrahydrofuran solution and slowly added dropwise to the flask at a flow rate of 2-3 drops per second. The reaction was maintained at this temperature for 4 hours. After the reaction was completed, insoluble substances were removed by vacuum filtration, and tetrahydrofuran was removed by rotary evaporation. The resulting solid mixture was purified by silica gel column chromatography, with the eluent being petroleum ether (PE) and ethyl acetate (EA) in a volume ratio of 10:1. He-BSCF was a yellow solid product (3.98 g, yield 45%, melting point: 103-105 °C).

[0117] The proton spectrum data of He-BSCF are as follows: 1 H NMR (400MHz, CDCl3) δ10.03(s,1H),8.47(dd,J=8.3,1.4Hz,1H),7.97(d,J=16.0Hz,1H) ,7.75–7.66(m,3H),7.45–7.33(m,2H),7.03(td,J=7.6,1.4Hz,1H),7.00–6.88(m,2H), 5.86(ddt,J=16.9,10.3,6.6Hz,1H),5.08(dq,J=17.1,1.7Hz,1H),5.02(dq,J=10.3,1. 5Hz,1H),4.06(t,J=6.4Hz,2H),2.17(q,J=7.1Hz,2H),1.92–1.80(m,2H),1.62(m,2H).

[0118] The carbon spectral data of He-BSCF are 13 C NMR (100MHz, CDCl3) δ184.18,162.26,158.94,148.56,138.84,138.39,136.86,131.97,131 .34,127.10,125.05,124.33,120.25,115.23,115.09,114.91,68.08,33.39,28.56,25.27.

[0119] Example 8

[0120] The preparation of Ipr-BSCF, a disulfide compound with the ability to initiate and reduce volume shrinkage in LED photopolymerization, is described below:

[0121]

[0122] p-Hydroxybenzaldehyde (1.22 g, 10 mmol), anhydrous potassium carbonate (2.07 g, 15 mmol), potassium iodide (0.02 g, 0.1 mmol), and 1-bromoisopentane (2.27 g, 15 mmol) were dissolved in 30 mL of acetonitrile solution and added to a 100 mL single-necked flask. The mixture was stirred at 80 °C with a magnetic stirrer for 6 h. The acetonitrile solution was then removed by rotary evaporation. The resulting white solid mixture was dissolved in 20 mL of deionized water, extracted three times with ethyl acetate, and the organic phase was dried overnight with anhydrous sodium sulfate. Finally, the ethyl acetate was removed to obtain intermediate A (1.73 g, 90%).

[0123] The proton NMR data of intermediate A are as follows: 1 H NMR(400MHz, CDCl3)δ9.90(s,1H),7.89–7.81(m,2H),7.05–6.97(m,2H),4.0 9(t,J=6.6Hz,2H),1.87(m,1H),1.73(q,J=6.7Hz,2H),1.00(d,J=6.6Hz,6H).

[0124] The carbon spectrum data of intermediate A are as follows: 13 C NMR (100MHz, CDCl3) δ190.85,164.26,132.01,129.75,114.76,66.82,37.74,25.03,22.55.

[0125] Take 50 mL of anhydrous ethanol solution and add it to a 250 mL single-necked flask. Add potassium hydroxide (1.68 g, 30 mmol) to the flask under ice-water bath conditions and stir thoroughly with a magnetic stirrer. Dissolve pyruvate (1.76 g, 20 mmol) in 15 mL of anhydrous ethanol solution and slowly add it dropwise to the flask. Then dissolve intermediate A (3.84 g, 20 mmol) in 15 mL of anhydrous ethanol solution and add it dropwise to the flask at the same slow flow rate. Continue the reaction under ice-water bath conditions for 1 h. Remove the ice-water bath and raise the system temperature to room temperature, continuing the reaction for another 5 h. Remove the anhydrous ethanol using a rotary evaporator. Dissolve the resulting carboxylate in deionized water and repeatedly extract with ethyl acetate to remove unreacted starting material. Adjust the pH of the aqueous phase to approximately 2-3 using dilute hydrochloric acid. Finally, extract the organic matter from the aqueous phase with ethyl acetate until the aqueous phase is clear and transparent. Dry the organic phase overnight with anhydrous sodium sulfate. Finally, remove ethyl acetate to obtain intermediate B (2.78 g, 53%).

[0126] The proton NMR data of intermediate B are as follows: 1 H NMR(400MHz, DMSO-d6)δ7.66–7.59(m,3H),7.13(d,J=8.0Hz,1H),6.92–6.87(d, J=4.0Hz,2H),4.01–3.94(m,2H),1.73–1.58(m,3H),0.93–0.85(d,J=3.5Hz,6H).

[0127] The carbon spectrum data of intermediate B are as follows: 13 C NMR (100MHz, DMSO-d6) δ186.26,165.20,162.09,131.57,126.74,119.30,115.47,66.69,39.74,37.71,24.99,21.07.

[0128] Intermediate B (2.62 g, 10 mmol) was dissolved in 20 mL of tetrahydrofuran solution and added to a 100 mL single-necked flask. The mixture was stirred thoroughly with a magnetic stirrer under ice-water bath conditions. Oxaloyl chloride (1.32 g, 15 mmol) was dissolved in 10 mL of tetrahydrofuran solution and slowly added dropwise to the flask at a flow rate of 2-3 drops per second. After the addition was complete, one drop of DMF was added as a catalyst, and the reaction was maintained at an ice-water bath for 0.5 h. Tetrahydrofuran and excess oxaloyl chloride were removed by rotary evaporation under reduced pressure to obtain intermediate C. Using 20 mL of tetrahydrofuran as a solvent, 2,2'-dithiodiphenylamine (1.24 g, 5 mmol) and triethylamine (1.01 g, 10 mmol) were added to a 100 mL single-necked flask and stirred thoroughly with a magnetic stirrer under ice-water bath conditions. Intermediate C was dissolved in 10 mL of tetrahydrofuran solution and slowly added dropwise to the flask at a flow rate of 2-3 drops per second. The reaction was maintained at this temperature for 4 hours. After the reaction was completed, insoluble substances were removed by vacuum filtration, and tetrahydrofuran was removed by rotary evaporation. The resulting solid mixture was purified by silica gel column chromatography, with the eluents being petroleum ether (PE) and ethyl acetate (EA) in a volume ratio of 15:1. Ipr-BSCF was a yellow solid product (1.84 g, yield 50%, melting point: 80-82 °C).

[0129] The proton NMR data of Ipr-BSCF are 1 H NMR(400MHz, CDCl3)δ10.03(s,1H),8.47(dd,J=8.3,1.3Hz,1H),7.98(d,J=16.0Hz,1H),7.77–7.66(m,3H),7.45–7.33(m,2H),7 .03(td,J=7.6,1.4Hz,1H),7.02–6.94(m,2H),4.09(t,J=6.6Hz,2H),1.88(m,1H),1.74(q,J=6.7Hz,2H),1.01(d,J=6.6Hz,6H).

[0130] The carbon spectral data of Ipr-BSCF are 13 C NMR (100MHz, CDCl3) δ184.17,162.31,158.94,148.59,138.84,136.86,131.97,131 .35,127.05,125.04,124.31,120.23,115.17,115.10,66.70,37.82,25.05,22.59.

[0131] Example 9

[0132] The purpose of Example 9 is to illustrate that the disulfide compounds prepared in Examples 1-8 have absorption at 455 nm.

[0133] Using anhydrous acetonitrile as solvent, eight synthesized disulfide compounds, O-BSCF, Me-BSCF, BSCF, Br-BSCF, Mp-BSCF, Ha-BSCF, He-BSCF, and Ipr-BSCF, were prepared into concentrations (c) of 1×10⁻⁶ using 50 mL volumetric flasks. - 4 mol L -1 Standard solutions were prepared. Appropriate amounts of the standard solutions were added to cuvettes, with the liquid level reaching two-thirds of the cuvette's height. The cuvettes were then placed in a UV-Vis spectrophotometer to measure the absorbance (A) of eight disulfide compounds, with the UV-Vis absorption range being 200-500 nm. The molar extinction coefficient at the corresponding wavelength was then calculated using Lambert-Beer's law (A = ε × c × L, L = 1 cm).

[0134] The UV-Vis absorption spectra of eight disulfide compounds, along with their maximum absorption wavelengths and corresponding molar extinction coefficients at specific wavelengths, are shown below. Figure 2 , Figure 3 As shown in Table 2, all eight disulfide compounds exhibit visible light absorption at 455 nm, suggesting their potential application in 455 nm LED photopolymerization systems.

[0135] Table 2. Maximum absorption wavelengths (λ) of eight disulfide compounds max ) and its molar extinction coefficient (ε) at specific wavelengths.

[0136]

[0137] Example 10

[0138] The purpose of Example 10 is to demonstrate that the disulfide compounds prepared in Examples 1-8 have a good ability to initiate the photopolymerization of (meth)acrylate monomers under irradiation conditions of 455 nm LED light source.

[0139] A composite monomer was prepared by mixing triethylene glycol dimethacrylate (TEGDMA) and bisphenol A glycidyl methacrylate (Bis-GMA) in a mass ratio of 6:4. The disulfide compound prepared in Examples 1-8 was added at a content of 1 wt% as the photoinitiator, and a composite initiator consisting of 1 wt% of the commercial photoinitiator camphorquinone (CQ) and 2 wt% of dimethylaminoethyl methacrylate (DMAEMA) was used as a control group. A 455 nm wavelength LED light source was used as the irradiation source, with a light intensity of 100 mW cm⁻¹. -2The double bond conversion rate of the photosensitive resin during polymerization was monitored using a real-time infrared spectrometer (Thermo Fisher Scientific, Nicolet 5700). Measurements were taken at 1660-1600 cm⁻¹. -1 Changes in band area over time.

[0140] from Figure 4 , Figure 5 Double bond conversion curve and Figure 6 , Figure 7 The double bond conversion rate curves show that, after 200 s of illumination, without the addition of other photoinitiators, under a 455 nm LED, the double bond conversion rates of the photopolymerization systems initiated by Me-BSCF, BSCF, and Br-BSCF reached over 64%, while the double bond conversion rates of the photopolymerization systems initiated by O-BSCF, Mp-BSCF, Ha-BSCF, He-BSCF, and Ipr-BSCF reached over 70%, all higher than the control group (CQ / DMAEMA) (62.5%). Furthermore, their maximum double bond conversion rates were 1.69% s⁻¹. -1 1.48%s -1 1.55%s -1 1.47%s -1 1.20%s -1 1.22%s -1 1.31%s -1 and 1.43%s -1 This indicates that all eight disulfide compounds have a good ability to initiate the polymerization of (meth)acrylate monomers and can be used in photopolymerization systems for 455nm LED light sources.

[0141] Example 11

[0142] The purpose of Example 11 is to demonstrate that when the disulfide compound prepared in Example 5 is added in greater quantities under 455nm LED light source irradiation, the final double bond conversion rate and double bond conversion rate of the photopolymerization of (meth)acrylate monomers are both improved.

[0143] Bisphenol A glycidyl methacrylate (Bis-GMA) and triethylene glycol dimethacrylate (TEGDMA) (4:6, mass ratio) were selected as commercial monomers, and the disulfide compound Mp-BSCF prepared in Example 5 was used as the photoinitiator to prepare the photosensitive resin. The addition content of Mp-BSCF was 2.5 wt%, 5.0 wt%, 7.5 wt%, and 10.0 wt% (as a percentage of the total monomer weight), respectively. A 455 nm wavelength LED light source was used as the irradiation source, and the light intensity was 100 mW·cm. -2The double bond conversion rate of the photosensitive resin during polymerization was monitored using a real-time infrared spectrometer (Thermo Fisher Scientific, Nicolet 5700). Measurements were taken at 1660-1600 cm⁻¹. -1 Changes in band area over time.

[0144] from Figure 8 Double bond conversion curve and Figure 9 The double bond conversion rate curves show that, under 455nm LED illumination, with increasing Mp-BSCF content, the double bond conversion rate of the photopolymerization system increased from 75.0% to 82.0% after 200s of illumination, and the maximum polymerization rate also increased from 1.49% to 82.0% with increasing Mp-BSCF content. -1 Increased to 2.02% -1 The above results further demonstrate that the synthesized disulfide compound possesses excellent initiation capabilities.

[0145] Example 12

[0146] The purpose of Example 12 is to demonstrate that the disulfide compounds prepared in Examples 1-8 have a good ability to reduce volume shrinkage during free radical photocuring under irradiation with a 455nm LED light source.

[0147] Taking the disulfide compound Mp-BSCF prepared in Example 5 as an example, it was compared with the commercial photoinitiator camphorquinone (CQ) / dimethylaminoethyl methacrylate (DMAEMA) system (1:2, mass ratio). Bisphenol A glycidyl methacrylate (Bis-GMA) and triethylene glycol dimethacrylate (TEGDMA) (4:6, mass ratio) were selected as commercial monomers to formulate the photosensitive resin, and the formulation is shown in Table 3.

[0148] Table 3 Formulations of photosensitive resins with different Mp-BSCF contents

[0149]

[0150] A rubber mold with a diameter of 3 mm and a height of 1 mm was placed on a glass slide. The photosensitive resin prepared in Table 3 was then added to the rubber mold, and a 10-filament PE film was applied for oxygen barrier treatment. The prepared sample was placed on a stage and irradiated with a 455 nm LED point light source for 5 minutes, with a light intensity of 100 mW / cm² on the sample surface. -2 The change in surface height of the photosensitive resin before (l1) and after (l2) illumination was tested using a laser displacement sensor. Each sample was measured in triplicate, and the volume shrinkage rate was calculated using the following formula:

[0151]

[0152] fromFigure 10 The test results show that the volume shrinkage rate of the control group photopolymerization system Mp-BSCF-0, initiated by the commercial photoinitiator CQ / DMAEMA, was 8.48%. As the Mp-BSCF content increased from 2.5 wt% to 10.0 wt%, the volume shrinkage rate of the Bis-GMA / TEGDMA photopolymerization system gradually decreased from 7.52% to 4.24%, a reduction of half compared to the control group Mp-BSCF-0. This indicates that the addition of Mp-BSCF can effectively reduce the volume shrinkage rate of the photopolymerization system.

[0153] Example 13

[0154] The purpose of implementation 13 is to illustrate that adding the disulfide compounds prepared in Examples 1-8 can improve the thermal stability of the polymer film to a certain extent.

[0155] Taking the disulfide compound Mp-BSCF prepared in Example 5 as an example, the photosensitive resin was prepared according to the formulation in Table 3. Different photopolymerization systems were continuously irradiated with a 455nm LED light source for 10 minutes to cure and form films, with the light intensity on the sample surface being 100mW / cm². -2 Approximately 5 mg of the polymer film was weighed using an analytical balance and placed in a thermogravimetric analyzer (DTG-60AH) for thermal stability testing under nitrogen purging. The initial temperature was 30℃, the maximum temperature was 700℃, and the heating rate was 10℃ / min. -1 .

[0156] The test results are shown in Table 4 and Figure 11 As shown in Table 4, the initial decomposition temperature T decreases with increasing Mp-BSCF content in the photopolymerization system. 5％ T max1 and T max2 All of these values ​​increased, indicating that the addition of the prepared disulfide compound can improve the thermal stability of the polymer film to some extent.

[0157] Table 4. Thermogravimetric parameters of polymer films with different MP-BSCF content.

[0158]

[0159] Example 14

[0160] Example 14 aims to demonstrate that the polymer film prepared by adding the disulfide compounds prepared in Examples 1-8 has good abrasion resistance.

[0161] Taking the disulfide compound Mp-BSCF prepared in Example 5 as an example, the photosensitive resin was prepared according to the formula in Table 3. The prepared photosensitive resin was continuously irradiated with a 455nm LED light source for 10 minutes to cure into a film, wherein the light intensity on the sample surface was 100mW / cm². -2 .

[0162] The obtained polymer film was placed on a stage and fixed with a pressure plate. Its abrasion resistance was tested using a Malaysian 7017R rubber under a 500g load. The friction distance was 10cm, and the number of abrasion cycles was 4000. The mass (m) of the polymer film was recorded every 500 abrasion cycles. x Each group of samples was measured in parallel three times, and the frictional loss of the samples was calculated using the following formula:

[0163] Friction loss = m0 - m x

[0164] The test results are shown in Table 5. The friction loss of the Mp-BSCF polymer films was slightly lower than that of the control group CQ / DMAEMA system, i.e., the Mp-BSCF-0 sample. The friction loss rates of Mp-BSCF-0, Mp-BSCF-5.0, and Mp-BSCF-10.0 after 4000 cycles were 22.5 mg, 21.3 mg, and 19.8 mg, respectively. This demonstrates that the photocurable film containing Mp-BSCF has good abrasion resistance.

[0165] Table 5. Friction loss rate of disulfide compound-cured films

[0166]

[0167] Example 15

[0168] The purpose of Example 15 is to illustrate that as the amount of disulfide compound added in Examples 1-8 increases, the hardness of the prepared polymer film also increases.

[0169] Taking the disulfide compound Mp-BSCF prepared in Example 5 as an example, the photosensitive resin was prepared according to the formula in Table 3. The prepared photosensitive resin was continuously irradiated with a 455nm LED light source for 10 minutes to cure into a film, wherein the light intensity on the sample surface was 100mW / cm². -2 Place the polymer film on the stage of the Shore hardness tester, insert the needle into the surface of the polymer film and record the Shore hardness tester reading. Each sample is measured in parallel three times.

[0170] Test results are as follows Figure 12As shown in the figure, the Shore hardness of the polymer film increases from 82.7 HD to 88.8 HD as the content of Mp-BSCF in the photopolymerization system increases. Compared with the control group Mp-BSCF-0 (81.2 HD), the hardness of the polymer film containing Mp-BSCF is slightly higher than that of the photopolymerization system induced by CQ / DMAEMA.

[0171] Example 16

[0172] Example 16 aims to demonstrate that the disulfide compounds prepared in Examples 1-8 have photobleaching properties.

[0173] Taking the disulfide compound O-BSFC prepared in Example 1 as an example, Bis-GMA / TEGDMA (4:6, mass ratio) was selected as the monomer, and O-BSFC was used as the initiator to prepare a photosensitive solution with an initiator concentration of 1 wt%. The photosensitive solution was dropped into a silicone mold with a diameter of 5 mm and a depth of 1.5 mm, and covered with a PE film with a thickness of 10 mils to isolate it from oxygen. Then, light with an intensity of 100 mW / cm² was used. 2 The photosensitive liquid was irradiated with a 455nm LED light source for 200 seconds, and the color change before and after curing was observed. The results are as follows: Figure 13 As shown. The photosensitive liquid containing O-BSFC prepared in this invention is deep yellow. When irradiated with a 455nm LED light source for 120 seconds, the color of the cured film lightens, and after irradiation for 200 seconds, the cured film becomes colorless, indicating that O-BSFC exhibits good photobleaching performance under LED light source irradiation.

Claims

1. A cinnamoyl derivative disulfide compound of general formula (Ⅰ): M represents Where R1, R2, R3, R 4 Any one of the groups in R1 and R5 is taken from: CH3O-、CH3-、H、Br、 The remaining groups in R1, R2, R3, R4, and R5 may be the same or different, and are independently selected from hydrogen, C1-C6 alkyl groups, and C1-C6 ether chains, with hydrogen, methyl, ethyl, n-propyl, and isopropyl being preferred; n ranges from 1 to 10.

2. A method for preparing the cinnamyl derivative disulfide compound of claim 1 is as follows: 1) Aromatic aldehyde 1, anhydrous potassium carbonate, potassium iodide and haloalkanes were dissolved in organic solvent 1 and added to a single-necked flask. The mixture was stirred evenly with a magnetic stirrer at 80°C and kept at this temperature for 12 hours. Then, organic solvent 1 was removed by rotary evaporation. The resulting mixture was dissolved in a certain amount of deionized water, extracted three times with organic solvent 2, and the organic phase was dried overnight with anhydrous sodium sulfate. Finally, organic solvent 2 was removed to obtain intermediate A. 2) Add organic solvent 3 to a single-necked flask. Under ice-water bath conditions, add a certain amount of alkaline substance 1 to the flask and stir evenly with a magnetic stirrer. Dissolve pyruvic acid in organic solvent 3 in a certain proportion and slowly add it dropwise to the flask. Then, dissolve intermediate A or aromatic aldehyde 2 in organic solvent 3 in a certain proportion and add it dropwise to the flask at the same slow flow rate. Continue the reaction under ice-water bath conditions for 1 hour. Then, raise the system temperature to room temperature and continue stirring with a magnetic stirrer for 5 hours. Remove organic solvent 3 by vacuum distillation and dissolve the resulting yellow solid in deionized water. Use organic solvent 2 as the organic phase to repeatedly extract the unreacted raw material in the system. Then, adjust the pH of the aqueous phase to about 2-3 with dilute hydrochloric acid and extract with organic solvent 2 until the aqueous phase is clear and transparent. Finally, remove organic solvent 2 by vacuum distillation to obtain intermediate B. 3) Dissolve intermediate B in organic solvent 4 and add it to a single-necked flask. Stir the mixture thoroughly with a magnetic stirrer under ice-water bath conditions. Dissolve oxaloyl chloride in organic solvent 4 and slowly add it to the flask at a flow rate of 2-3 drops per second. After the addition is complete, add one drop of organic solvent 5 as a catalyst. Keep the reaction at an ice-water bath for 0.5 h. Remove organic solvent 4 and excess oxaloyl chloride by vacuum distillation using a rotary evaporator to obtain intermediate C. Add an aromatic disulfide compound with active hydrogen and basic substance 2 to a single-necked flask and add a certain amount of organic solvent 4. Stir the mixture thoroughly with a magnetic stirrer under ice-water bath conditions. Dissolve intermediate C in organic solvent 4 and slowly add it to the flask at a flow rate of 2-3 drops per second. Keep the reaction at an ice-water bath for 4 h. After the reaction is complete, remove insoluble substances using a vacuum filtration device and remove organic solvent 4 using a rotary evaporator. Separate and purify the obtained solid mixture by silica gel column chromatography to obtain cinnamyl derivative disulfide compound.

3. The method according to claim 2, characterized in that, Organic solvent 1 is selected from anhydrous acetonitrile, ethyl acetate, dichloromethane, tetrahydrofuran, N,N-dimethylformamide, toluene, and xylene, preferably anhydrous acetonitrile; organic solvent 2 is selected from ethyl acetate, dichloromethane, toluene, and xylene, preferably ethyl acetate; organic solvent 3 is selected from anhydrous ethanol, anhydrous methanol, and isopropanol, preferably anhydrous ethanol; organic solvent 4 is selected from tetrahydrofuran, ethyl acetate, toluene, xylene, and anhydrous acetonitrile, preferably tetrahydrofuran; and organic solvent 5 is N,N-dimethylformamide.

4. The method according to claim 2, characterized in that, Aromatic aldehyde 1 is selected from 4-hydroxybenzaldehyde, 3-hydroxybenzaldehyde, 2-hydroxybenzaldehyde, 2,4-dihydroxybenzaldehyde, and 3,4-dihydroxybenzaldehyde, with 4-hydroxybenzaldehyde being preferred; aromatic aldehyde 2 is p-methoxybenzaldehyde, p-methylbenzaldehyde, benzaldehyde, and p-bromobenzaldehyde; the halogenated alkane is 1-bromohexane, 6-bromo-1-hexene, 1-bromoisopentane, and 1-bromo-2-(2-methoxyethoxy)ethane.

5. The method according to claim 2, characterized in that, Alkaline substance 1 is selected from potassium hydroxide, sodium hydroxide, magnesium hydroxide, and sodium hydride, preferably potassium hydroxide; alkaline substance 2 is selected from triethylamine, pyridine, imidazole, diisopropylamine, and 1,8-diazabicyclo[5.4.0]undec-7-ene, preferably triethylamine and imidazole; the molar ratio of alkaline substance 1 to pyruvic acid is 1.5:1 to 2:1, preferably 1.5:1; the molar ratio of intermediate A or aromatic aldehyde 2 to pyruvic acid is 1:1 to 1:1.5, preferably 1:1.5; the molar ratio of intermediate C to an aromatic disulfide compound with active hydrogen is 2.2:1 to 2.5:1, preferably 2.2:

1.

6. A composition cured by free radical photopolymerization, characterized in that, It includes the cinnamic yl derivative disulfide compound of claim 1.

7. The composition according to claim 6, characterized in that, The composition comprises 1% to 10% of the disulfide compound and 90% to 99% of the photoreactive resin or active monomer; or comprises 1% to 8% of the cinnamonyl derivative disulfide compound, 1% to 5% of the photoinitiator and 87% to 98% of the photoreactive resin or active monomer, based on the total weight of the composition.

8. The composition according to claim 7, characterized in that, The photoreactive resin is selected from one or more of epoxy (meth)acrylate resin, polyurethane (meth)acrylate resin, polyester (meth)acrylate resin, polyether (meth)acrylate resin, and acrylate-esterified poly (meth)acrylate resin; the active monomer is one or more of monofunctional, difunctional, or polyfunctional (meth)acrylate monomers; and the photoinitiator is selected from one or more of free radical photoinitiators.

9. The application of the cinnamyl derivative disulfide compound according to claim 1 in the field of LED photopolymerization.

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